SYDNEY - Southeast Asia's oceans are fast running out of fish, putting the livelihoods of up to 100 million people at risk and increasing the need for governments to support the maintenance of fish stocks, an Australian expert said.

Fisheries in the region had expanded dramatically in recent decades and Indonesia, Thailand, Vietnam and the Philippines were now in the top 12 fish producing countries in the world, Meryl Williams said in a paper for Australia's Lowy Institute.

"As the fourth largest country in world fish production, Indonesia is a fisheries giant. Yet ... Indonesian marine fisheries resources are close to fully exploited and a significant number in all areas are over-exploited," she said.

Williams, a former director general of the international WorldFish Center, said the number of fishers was still increasing in most Southeast Asian countries despite a trend since the 1980s to close frontiers due to territorial claims and overfishing.

In the Gulf of Thailand, the density of fish had declined by 86 percent from 1961 to 1991, while between 1966 and 1994 the catch per hour in the Gulf by trawlers fell more than sevenfold.

In Vietnam, a new fishing power and a rising source of imports by Australia, the total catch between 1981 and 1999 only doubled despite a tripling of capacity of the fishing fleet -- a sure sign that fishing was reaching capacity, she said.

In the Gulf of Tonkin, where Vietnam shares resources with China, the record was even worse with fish catch per hour in 1997 only a quarter of that in 1985.

"In the Philippines, most marine fisheries were overexploited by the 1980s, with catch rates as low as 10 percent of rates when these areas were lightly fished," she said.

Williams said Southeast Asian fisheries were serviced by a plethora of regional bodies and agreements, but few acted effectively on illegal fishing and shared stock management.

At the same time, illegal fishing was "dynamic, creative, clever and usually one step ahead of authorities.

A Southeast Asian government may issue a single fishing license only to find it being used by four different boats, she said. In Indonesia, foreign fishing vessels, often Chinese in joint-ventures, operated on the "margins of legality" in a geographically vast archipelago.

Williams said Australia should step up collaboration with Southeast Asian countries to help manage fish stocks.

All of the world's fishing stocks will collapse before midcentury, devastating food supplies, if overfishing and other human impacts continue at their current pace, according to a global study published today by scientists in five countries.

Already, nearly one-third of species that are fished — including bluefin tuna, Atlantic cod, Alaskan king crab, Pacific salmon and an array in California fisheries — have collapsed, and the pace is accelerating, the report says.

If that trend continues, the study predicts that "100% of [fished] species will collapse by the year 2048, or around that," said marine biologist Boris Worm, who led the research team. A fishery is considered collapsed if catches fall to 10% of historic highs.

Without more protection soon, the world's ocean ecosystems won't be able to rebound from the shrinking populations of so many fish and other sea creatures, the scientists reported in the journal Science.

The report is the first comprehensive analysis of the potential consequences of ongoing declines in the oceans' diversity of life. In recent years, marine scientists have warned of the extreme toll of overfishing in many regions, but the new report, global in scope, offers one of the grimmest predictions for the future of the world's fisheries.

Yet there is hope, the scientists concluded: "Available data suggest that at this point, these trends are reversible."

If more protections are put into place, such as new marine reserves and better-managed commercial fisheries, seafood supplies will surge and the oceans can recover, they said.

"The good news is that it is not too late to turn things around," said Worm, an assistant professor of marine conservation biology at Dalhousie University in Halifax, Canada. "It can be done, but it must be done soon."

The authors are 14 marine scientists, eight of them from California institutions, including Scripps Institution of Oceanography, Stanford University's Hopkins Marine Station, Santa Barbara's National Center for Ecological Analysis and Synthesis and UC Davis. Funding came from the National Science Foundation, the University of California and UC Santa Barbara.

Group disputes findings

A U.S. fishing industry group, the National Fisheries Institute, disputed the pessimistic findings, saying that fishermen and government already had acted and that federal data showed that "more than 80% of fish stocks are sustainable and will provide seafood now and for future generations."

"Fish stocks naturally fluctuate in population. Fisheries scientists around the world actively manage stocks and rebuild fisheries with a low sustainable population," the institute said.

The group said that for the last 25 years, catches had been steady, with wild fisheries providing 85 million to 100 million metric tons annually, and aquaculture — fish farming — helping to fill the growing demand.

The scientists, however, said they were confident of their predictions because they found "consistent agreement of theory, experiments, and observations across widely different scales and ecosystems."

"There's no question if we close our eyes and pretend it's all OK, it will continue along the same trajectory. Eventually, we're going to run out of species," Worm said.

Delving into recent catch data around the world as well as 1,000 years of historical archives in areas such as the San Francisco Bay, the team reported that estuaries, coral reefs, wetlands and oceanic fish were all "rapidly losing populations, species or entire functional groups."

Scarcity of a highly nutritious food supply for the world's growing human population would be the most visible effect of declining ocean species. But the scientists said other disruptions also were occurring as ocean ecosystems unraveled, species by species.

Biologists have long debated the lasting effect of removing a few species from oceans. The authors of the new report conclude that it sabotages oceans' stability and their recovery from stresses.

"Our analyses suggest that business as usual would foreshadow serious threats to global food security, coastal water quality and ecosystem stability, affecting current and future generations," the report says.

Not just humans, but other creatures are in danger of food shortages, biologists say.

"Animals like seals, dolphins and killer whales eat fish. If we strip the ocean of these kinds of species, other animals are going to suffer," said coauthor Stephen Palumbi of Stanford, who specializes in marine evolution and population biology.

Many scientists not involved in the study echoed its findings Thursday, saying they were witnessing symptoms of crashing fish populations. P. Dee Boersma, a University of Washington scientist who has observed Argentina's depleted penguin populations travel farther in search of food, said, "This message of collapse and long-term damage is an important one."

In Maine, marine scientist Robert Steneck said depletion of cod and other fish triggered an imbalance that caused lobster populations to surge and left the region with a fragile and unsustainable "monoculture that is the direct result of the overfishing Worm and others describe."

The new report documents "why ocean biodiversity matters," said Jane Lubchenco, an Oregon State University professor and member of the Pew Oceans Commission. "It's clear from the analysis that the problems are very real and getting worse, but — and here's the good news — that the downward spiral can be reversed."

The strength of the new report "lies in the breadth of the array of information the authors used for their analysis," said Andrew Sugden, Science's international managing editor.

First, they analyzed 32 experiments that manipulated species in small areas and reported "a strikingly general picture": Decreased types of species spurred ecosystem-wide problems.

Also, the team assessed United Nations catch data since 1950 for all 64 of the Earth's large marine ecosystems, including the Bering Sea, California Current and Gulf of Mexico.

Changes in native species were also tracked over a 1,000-year period in 12 coastal regions, including San Francisco, Chesapeake and Galveston bays. About 91% suffered at least a 50% decline, and 7% were extinct.

Mirroring declines

Worm said similarities in all the data "surprised, even shocked" him and his colleagues. The smallest experiments — a few square meters — mirrored the declines seen in ocean basins.

Palumbi warned that "this century is the last century of wild seafood" unless there are fundamental changes in managing ocean ecosystems.

At 48 areas already protected by marine reserves and fishery closures in California, Florida, the Philippines, the Caribbean and elsewhere, species declines reversed and catches nearby increased fourfold, the study says.

Coauthor Heike Lotze, also of Dalhousie University, reported in June that "human history rather than natural change" drove declines.

"Overfishing is almost certainly the most important factor, but habitat destruction, pollution and climate change may also contribute," Worm said.

Japan's huge appetite for tuna will take the most sought-after stocks to the brink of commercial extinction unless more rigid quotas are agreed, wildlife campaigners warned yesterday.

WWF said that although Japan was the main culprit, burgeoning demand for tuna from other countries, such as China, had increased the threat to stocks.

"Tuna are fast disappearing, with important stocks at high risk of commercial extinction due to weak management," the group, formerly known as the World Wildlife Fund, said in a statement. "Atlantic bluefin [tuna], used for high-end sushi and sashimi, is massively overfished and the spawning stock of southern bluefin in the Indian Ocean is down about 90%."

The warning came at the start of a five-day meeting in Kobe, Japan, of the world's five biggest tuna fisheries management organisations, which cover 77 countries and regions. "We are deeply concerned about the future of global tuna stock. We must strengthen our cooperation to tackle the issue," said Toshiro Shirasu, director general of the Fisheries Agency in Japan.

About 2m tonnes of tuna were caught worldwide in 2004 and 530,000 tonnes went to Japanese markets in 2005, according to the Fisheries Agency.

Japan, which consumes more than half of the world's catch of at-risk Atlantic bluefin tuna, admits overfishing, but blames poor communication between its fishermen and denies it has fished illegally. Last October it agreed to halve its catch of southern bluefin to 3,000 tonnes a year over the next five years.

A month later, the International Commission for the Conservation of Atlantic Tuna agreed to cut this year's bluefin tuna quota in the eastern Atlantic and Mediterranean from 32,000 to 29,500 tonnes, raising fears in Japan of a steep price rise.

New quotas will not be decided this week, but campaigners hope members of the five regional bodies responsible for managing tuna stocks will agree to share data.

"For the first time, there's general agreement by the governments that something significant has to be done," Alistair Graham of WWF told Reuters.

Proposals include requiring fishermen to produce certificates of origin for their tuna catches and for fish to be monitored between capture and market.